A unit of Madras sappers from the Corps of Engineers of the Indian army reached the partially-collapsed Silkyara-Barkot tunnel in Uttarkashi Sunday morning to assist the rescue operations.
Six plans are being deployed to rescue the trapped 41 workers, with the best solution being horizontal drilling, news agency PTI reported the National Disaster Management Authority (NDMA) as saying.
Machines for undertaking sideways drilling (perpendicular drilling) are expected to reach the rescue site during night.
At least 86 metres of digging is required to reach the 41 workers.
Considered as the second best option, the work on vertical drilling started around noon and 15 meters of drilling has already been completed, PTI reported National Disaster Management Authority (NDMA) Member Lt Gen (retd) Syed Ata Hasnain as saying.
Meanwhile, 13.09 metre of the stuck auger machine blade remains to be cut out as of 1 pm on Sunday, Neeraj Khairwal, Secretary at the Uttarakhand government, said.
Earlier, Uttarakhand Chief Minister Pushkar Singh Dhami said that the plasma machine brought from Hyderabad had started working on Sunday morning, cutting the blade from the auger machine from where it is stuck in an obstruction.